Question

Which of the following statements about Base Excision Repair are true?

I. Base Excision Repair can detect non-helix distorting mutations
II. Base Excision repair will remove the affected base using a Glycosylase Enzyme.
III. An AP Endonuclease will then remove the damaged DNA sequence, so DNA polymerase and ligase can finish the repairs.

(A) III only
(B) I and II only
(C) I and III only
(D) I, II and III

Answer 1

Answer (D) I, II and III are all true statements regarding Base Excision Repair, which detects non-helix distorting mutations, uses a glycosylase enzyme to remove affected bases, and involves an AP endonuclease for removing the DNA sequence to complete repairs.

Step-by-step explanation:

The correct answer to which statements about Base Excision Repair are true is: (D) I, II and III. Base Excision Repair operates as follows:

• It can detect and correct non-helix distorting mutations caused by issues such as oxidation or deamination. This is a true statement, corresponding to the first point.
• Glycosylase enzymes are indeed responsible for recognizing and removing the damaged bases, which aligns with the second point.
• Once the affected base is removed, an AP endonuclease cuts the DNA backbone at that spot. Then a phosphodiesterase removes the remaining sugar-phosphate. DNA polymerase adds the correct nucleotide, and DNA ligase seals the nick, concluding the repair process. This series of events confirms the third statement.

Thus, all provided statements (I, II, and III) are integral parts of the Base Excision Repair mechanism.